Datasheet

Analog-to-Digital Converter (ADC)
Functional Description
MC68HC908GR8 — Rev 4.0 Technical Data
MOTOROLA Analog-to-Digital Converter (ADC) 81
Figure 5-1. ADC Block Diagram
5.4.1 ADC Port I/O Pins
PTB5/ATD5–PTB0/ATD0 are general-purpose I/O (input/output) pins
that share with the ADC channels. The channel select bits define which
ADC channel/port pin will be used as the input signal. The ADC
overrides the port I/O logic by forcing that pin as input to the ADC. The
remaining ADC channels/port pins are controlled by the port I/O logic
and can be used as general-purpose I/O. Writes to the port register or
DDR will not have any affect on the port pin that is selected by the ADC.
Read of a port pin in use by the ADC will return a logic 0.
INTERNAL
DATA BUS
READ DDRBx
WRITE DDRBx
RESET
WRITE PTBx
READ PTBx
PTBx
DDRBx
PTBx
INTERRUPT
LOGIC
CHANNEL
SELECT
ADC
CLOCK
GENERATOR
CONVERSION
COMPLETE
ADC
(V
ADIN
)
ADC CLOCK
CGMXCLK
BUS CLOCK
ADCH4–ADCH0
ADC DATA REGISTER
AIEN COCO
DISABLE
DISABLE
ADC CHANNEL x
ADIV2–ADIV0 ADICLK
VOLTAGE IN
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cale Semiconductor,
I
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